1. Field of the Invention
The present invention relates to a surgical manipulator system, which includes a manipulator to be inserted into a body cavity of a subject and which is designed to remote-control the manipulator to make diagnosis or perform a surgery.
2. Description of the Related Art
In recent years, transcutaneous endoscope surgery has been performed in which an endoscope or a medical instrument is inserted into a body cavity through a hole cut in the body wall (e.g., the abdominal wall) to perform various treatments in the body cavity. This is because transcutaneous endoscope surgery involves no large-scale incision and is therefore scarcely invasive to the patient. This type of surgery is now widely performed to extract the gallbladder or a part of either lung.
To perform a successful transcutaneous endoscope surgery, it is desirable that the endoscope or the instrument inserted in the body cavity be manipulated in as broad a space as possible within the body cavity. An endoscope or an instrument a surgeon can manipulate with one hand is a straight one which has but little freedom of operation. Due to the little freedom of operation, it is difficult for a surgeon to orient the endoscope or instrument in order to observe the target object at a desired angle or to treat the target object, even if he or she has managed to guide the endoscope or instrument to the object in the body cavity. For example, the surgeon can hardly position an instrument holding a needle, so as to drive the needle perpendicular to a suture line in his or her effort to suture an organ located in the body cavity.
This problem with transcutaneous endoscope surgery is solved by the use of a surgical manipulator with a multi-joint insertion section which has great operation freedom. A surgical manipulator system which holds an endoscope or a medical instrument and which is manipulated by a surgeon is disclosed in U.S. Pat. No. 5,217,003. This system comprises a manipulator which has an actuator and a multi-joint insertion section for holding an endoscope or an instrument. The actuator drives the joints of the insertion section independently, whereby the insertion section is easily guided to a target organ located in a body cavity.
When the multi-joint insertion section is operated to orientate the endoscope or instrument at a desired angle to the target organ, some of the joints may contact another organ in the body cavity. Further, when the patient moves while undergoing transcutaneous endoscope surgery, the affected part moves, too, making it difficult for the surgeon to excise that part precisely.
Two types of surgical manipulator systems are available, each comprising a remote-control device, a manipulator and a TV monitor. The TV monitor displays an image of the affected part in a body cavity, which has been obtained through an endoscope inserted in the body cavity. In the system of the first type, the surgeon operates a joy stick used as the remote-control device, while looking at the image of the affected part on the TV monitor, thereby operating the manipulator in the same way in the body cavity. In the system of the second type, generally known as "master-slave system," the surgeon operates a master manipulator used as the remote-control device, while looking at the image on the TV monitor, thereby operating the slave manipulator in the same manner in the body cavity.
In either system, the remote-control device is physically separated from the manipulator. Therefore, the directions in which the remote-control device and the manipulator may move are determined by the positional relation in which the device and the manipulator are arranged. In some cases, the coordinate system for the manipulator may be orientated differently from the coordinate system for the remote-control device.
In the case of a surgical manipulator system which comprises a plurality of master manipulators and a plurality of slave manipulators, the master manipulators are usually located at the bedside close to the surgeon so that he or she can operate them, whereas the slave manipulators are arranged opposite the bedside since no space is available at any other bedside. To state another way, the master manipulators and the slave manipulators cannot be located at the same bedside in most cases. As a consequence, when the surgeon moves the corresponding master manipulator to the right in order to move the slave manipulator in the same direction, a slave manipulator may move to the left. In other words, the coordinate system for the slave manipulators is orientated differently from that for the master manipulators, increasing the possibility that a slave manipulator moves in a direction other than the very direction in which it should move as the surgeon desires.
Even if the slave manipulators are arranged at the same bedside as the master manipulators, they should be spaced away from the master manipulators so as not to interfere with the master manipulators. Hence, the slave manipulators must be orientated differently from the master manipulators. In this case, too, any slave manipulator may move in a direction other than the direction in which it should move as the surgeon desires.
When manipulators each holding an endoscope or an instrument are independently operated by using remote-control devices, to thereby perform surgery, each manipulator is moved in the direction which is determined by the positional relationship between the remote-control devices, the positional relation between the manipulators and the positional relation between each manipulator and the associated remote-control device. That is, the direction in which each manipulator can be moved is restricted. In some case, the manipulator may be moved in an undesirable direction.
In the master-slave manipulator system, so-called "bilateral control" is employed to provide a surgeon a sense of immediacy. Bilateral control consists in transmitting any force on the slave manipulator to the master manipulator and hence to the person operating the master manipulator. To enhance visual sense of immediacy, a 3D (3-dimensional) image of the object being treated is displayed on a TV monitor installed near the master manipulator.
Since the master manipulator is located far from the object, it cannot abut on the object no matter how the surgeon operates the master manipulator. Hence, the surgeon is likely to operate the master manipulator excessively, whereby the slave manipulator collides with the object excessively. If this happens, an excessive force is exerted on either the object or the slave manipulator, possibly damaging the object or the slave manipulator. To prevent such damage, the surgeon may operate the master manipulator to move the master manipulator away from the object as soon as he or she sees that the slave manipulator gets too close to the object. His or her action may be too late. This is because a long time is required to process signals generated by the master manipulator and to supply the signals to the slave manipulator.
The surgeon may manipulate the master manipulator without seeing the 3D image displayed on the TV monitor to give him or her visual sense of immediacy. In this case, the slave manipulator is likely to collide with the object, applying an excessive force on the object or receive an excessive reaction from the object.
Generally, the insertion section of a surgical manipulator is integral with an endoscope or a medical instrument. Neither the endoscope nor the medical instrument can be washed or sterilized, independently of the surgical manipulator. To wash and sterilize the endoscope or instrument, it is necessary to wash and sterilize the manipulator, as well. It would take much labor to wash and sterilize the manipulator which is large and massive.
When a manipulator having a medical instrument and a manipulator having an endoscope are simultaneously operated, they may interfere with each other during the surgical operation. If this takes place, the spaces in which the manipulators can move will be limited, inevitably reducing the operation freedom of both the medical instrument and the endoscope, and ultimately impairing the operability of the surgical manipulator system as a whole. To make matters worse, the instrument and the endoscope cannot be exchanged to assume each other's position since they are integral with the insertion sections of the respective manipulators. To release the manipulators from the mutual interference, it is necessary to remove the insertion sections from the body cavity, then to position the manipulators out of mutual interference, and finally to insert the insertion sections back into the body cavity. This sequence of operations is complex and time-consuming; it not only decreases the efficiency of the surgical operation, but also impose a great burden on the patient receiving the operation.
In the master-slave manipulator system, described above, the surgeon operates the master manipulator at a place remote from the slave manipulator and the patient, and therefore cannot attend the patient immediately in case the patient gets, for example, a heart attack, or falls into a critical condition. Nor can he or she attend the patient at once in case the patient suffers great bleeding which cannot be stopped by remote-controlling the slave manipulator, and the abdominal wall must be immediately incised in order to stop the bleeding. Another surgeon needs to stay by the patient to perform an emergency treatment such as heart massage, incision of the abdominal wall, or the like.